Carbon 13 H. pylori, short for H. pylori carbon 13 urea breath test, is used to check whether there is H. pylori infection in the body, with a normal value of 0-4, which is negative, indicating no H. pylori infection; >4 is positive, indicating the presence of H. pylori infection in the body, and other tests and clinical symptoms are needed to determine whether other gastric diseases are also present. The carbon 13 urea breath test clarifies the presence of H. pylori in the stomach by oral administration of carbon 13-labeled urea. H. pylori can produce urease, which breaks down carbon 13-labeled urea into ammonia and carbon dioxide and travels with the bloodstream to the lungs, where a positive carbon 13 can be detected on exhalation. If it is accompanied by epigastric discomfort, indigestion symptoms such as belching, acid reflux, nausea and poor appetite, as well as epigastric pain before and after eating and relieved after eating, diseases such as chronic gastritis or peptic ulcer need to be considered and prompt medical treatment is recommended. For example, when carbon 13 is negative, normal treatment of stomach discomfort is sufficient. If it is carbon 13 positive, eradication treatment for H. pylori is required. Clinically, a quadruple drug is commonly used, including 1 proton pump inhibitor + 1 bismuth + 2 antibiotics, commonly used omeprazole, colloidal bismuth subcitrate, amoxicillin, metronidazole, etc. It is recommended that treatment be carried out under the guidance of a doctor. In addition, it is important to note that the carbon 13 breath test can be affected by the medication the patient is taking, which may lead to the possibility of false positives and false negatives. For example, if the patient has recently taken proton pump inhibitor drugs such as omeprazole, or has taken anti-inflammatory drugs for gastrointestinal diseases or toothache, the test results may be affected. Therefore, if the patient has undergone H. pylori eradication treatment, it is recommended that the test be repeated after the treatment has been completed and the drug has been stopped for more than 1 month; if the patient is taking proton pump inhibitors or anti-inflammatory drugs, it is also necessary to return to the hospital for a follow-up test according to the time required by medical advice to make the test more accurate. In addition, fasting is required for the carbon 13 test.